1. Field
The present disclosure relates generally to aircraft and, in particular, to a method and apparatus for calibrating a control surface of the aircraft. Still more particularly, the present disclosure relates to a method and apparatus for setting a balance tab of the control surface.
2. Background
In flight, an aircraft will rotate about its center of gravity, a point which may be the average location of the mass of the aircraft. A three dimensional coordinate system may be defined through the center of gravity with each axis of the coordinate system perpendicular to the other two axes. The orientation of the aircraft may be the amount of rotation of the parts of the aircraft along the axes. The roll axis may lie along the length of the aircraft.
A roll motion may be caused by the deflection of the ailerons of the aircraft. The aileron may be a hinged section of a wing at the rear of each wing. The rear of each wing may be the trailing edge of each wing. The trailing edge of each wing may be the edge towards the aft of the aircraft. The ailerons work in opposition; when the right aileron goes in one direction, the left aileron goes in the opposite direction. Changing the angle of deflection at the rear of a wing will change the amount of lift generated by the wing. With greater downward deflection, the lift will increase in the upward direction; with greater upward deflection, the lift will decrease in the upward direction. Since the ailerons work in pairs, the lift on one wing increases as the lift on the opposite wing decreases. Because the forces are not equal, there may be torque about the center of gravity and the aircraft rotates about the roll axis. The pilot may use the torque about the center of gravity to turn the aircraft.
Additionally, a tab may be part of each aileron. The “tab” may also be referred to as a “balance tab.” The tab may be a hinged section of the aileron at the rear of each aileron. The rear of each aileron may be the trailing edge of each aileron. The trailing edge of each aileron may be the edge towards the aft of the aircraft. The tab may or may not be the entire length of the aileron. The tabs may move opposite to the direction of aileron movement to assist in positioning the aileron aerodynamically.
Rigging or adjustment of the aileron and tab may be performed during, and/or after, the initial assembly of the aircraft, as well as during maintenance and routine checkups. Flight testing and configuration may be performed after the initial assembly. During flight testing and configuration, the ailerons and tabs are adjusted to produce the desired aerodynamic effect. The adjustments are made before the first test flight is performed to check the accuracy of the adjustments. If the test flight results show unacceptable aileron positioning characteristics, more adjustments and test flights may be performed.
Therefore, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above.